High-gain antenna reflectors have been deployed in space for several decades. The configurations of such reflectors have varied widely as material science developed and as the sophistication of technology and scientific needs increased. However, some constants within the technology of antenna reflectors have emerged. First, an ideal contour for a deployed reflective surface of the antenna reflector is one which results in a parabolic configuration. Second, power and performance of an antenna system is directly related to the size of the deployed reflective surface. Thus, the optimum antenna reflector is one which, on deployment, assumes an, ideally, parabolic configuration and which possesses the largest practical reflective surface area.
Large diameter antenna reflectors pose particular problems during deployment. Likewise, large, completely rigid antennas are highly impractical to launch into space in a deployed position. Thus, large antennas are typically stored in a collapsed position within a payload space of a space vehicle prior to deployment. To maximize payload space within the space vehicle for other purposes, it is beneficial to minimize the storage space consumed by the collapsed antenna. In an attempt to minimize their required storage space, antennas are typically of a collapsible and/or a foldable construction.
At present, antenna reflectors of the collapsible or the foldable variety are of three design types. One design is a grid, or mesh type, antenna reflector that is closed like an umbrella. In its stowed position, the mesh antenna reflector achieves a reduced circumferential dimension. However, the reduction of the circumferential dimension results in a larger radial storage dimension. The radial storage dimension is typically reduced by folding the reflector.
In a second design, a solid surface antenna reflector and its supporting structure are folded against a side of a spacecraft prior to launch. For example, the solid surface antenna reflector may be attached to the spacecraft by means of a hinge. In this configuration, the antenna reflector is pivoted about the hinge to a closed position along side the spacecraft prior to launch. After launch, the reflector is deployed by pivoting the reflector to an open position away from the spacecraft.
Alternatively, an antenna reflector may include a reflector surface that comprises segmented petals, for example, commonly assigned U.S. Pat. No. 5,451,975, issued Sep. 19, 1995, entitled "Furlable Solid Surface Reflector", by Miller et al. Miller et al. teach a furlable solid surface reflector having several long, tapered petals which form a solid, continuously curved parabolic surface when in a deployed position, and which form a conical shape when in an undeployed, stored position.
In conventional segmented petal antenna reflectors, the segmented petals may be stored in various overlapped configurations. In a stowed position, the segmented petal antenna reflectors are collapsed to achieve a reduced circumferential dimension. However, as a reflector's surface area becomes large an increased number of joints and segments are required to collapse the reflector surface into manageable sized petals. Even with storage techniques that overlap the petals, the number of petals required to collapse an antenna reflector with a large surface area consumes significant storage space. Additionally, the larger the number of petals that comprise an antenna reflector the more complex the deployment mechanism becomes in order to reassemble the antenna reflector. A complex deployment mechanism may result in additional structural components which may increase the storage requirement of the collapsed antenna reflector within the payload of the space vehicle.
Thus, there remains a need for a storage method and apparatus that maximizes the deployed antenna reflector's surface area, minimizes the collapsed stowage requirement, and enables the deployed antenna reflector to assume a desired parabolic configuration.